Django form redirect using HttpResponseRedirect

So this can't be too hard but I can't figure it out...

I want my form in django (located at /file_upload/) to upload a file, add it to the database, and then redirect to a new page where the parameter is the id of the field that I've added in the database (located at /file/163/, say).

I've set up urls.py so that /file/163/ works just fine if you navigate there directly, but I don't know how to get there from /file/upload/.

My code is like this:

def add(request):
    if request.method == 'POST': # If the form has been submitted...
        form = UploadFileForm(request.POST, request.FILES)
        if form.is_valid():
            # do stuff & add to database
  my_file = FileField.objects.create()
            return HttpResponseRedirect(reverse('/file/', args=[my_file.id]))

I can't use this solution because I don't know what the field id is going to be until I've handled the form in views.py, so the redirect has to happen in views.py. I think.

Any thoughts?